Photodynamic and photothermal tumor therapy using phase-change material nanoparticles containing chlorin e6 and nanodiamonds

This paper describes the fabrication and evaluation of phase-change material (PCM) nanoparticles containing chlorin e6 (Ce6) and nanodiamonds (NDs) for photodynamic and photothermal approaches for tumor therapy, respectively. The temperature of the PCM nanoparticles containing NDs (ND/PCM, 0.5 mg/mL in water) is increased to 45 °C during laser exposure for 5 min. The singlet oxygen generation intensity of PCM nanoparticles containing Ce6 and NDs (Ce6/ND/PCM) is gradually increased with respect to the laser exposure time. Also, the release of Ce6 from Ce6/ND/PCM can be controlled in an on-and-off manner using laser. Cell ablation tests reveal that Ce6/ND/PCM greatly ablates KB cells upon laser exposure, which is attributed to both the temperature increase in the media and singlet oxygen generation by the released Ce6. In an animal model, tumor volume is notably reduced over time after the intratumoral injection of Ce6/ND/PCM and subsequent laser exposure with a higher efficiency compared to ND/PCM. The Ce6/ND/PCM can be a promising nanomedicine for tumor therapy.